The Tor Browser is safe for normal browsing. There are many illegal activities happening through this network. Simply accessing and viewing information is safe and legal. Your activity and interaction with this resource (such as making purchases of contraband) can be illegal and cause you harm.
Ashley Madison is not a safe site. In 2015, approximately 36 million users had their personal information exposed in a massive hack. An investigation found the site had negligently poor network security. The owners also engaged in fraudulent business practices including the creation of thousands of fake accounts.